1. Field of the Invention
The present invention relates to an innovation of sound coil for loudspeaker, especially referring to an improved structure for the sound coil of loudspeaker provided with multiple conducting wires to increase output power. Thus the production requires less coils and the size of loudspeaker is reduced.
2. Description of the Prior Art
Music is a part of human's civilization throughout the history. The ancestors passed down music to the next generations via musical notes and musicians. With the phonograph invented by Edison, people could record music in a brand new way. Now, stereo equipment has become an indispensable appliance for the leisure life. As a result of informational technological advancement, the sound output equipment is becoming more important than ever and, consequently, the loudspeakers with various functions and shapes have been presented to the market. Now the electric appliances are designed in a complicated manner and the loudspeaker has become smaller than before in order to save space.
Sound coil is an important part for loudspeaker. The conventional sound coil of loudspeaker comprises a cylinder provided with coils surrounding one end thereon. There are two discriminations for two conducting wires or single conducting wire. However, the number of layers of coils surrounding the cylinder are the same for all sound coils. In general, the conventional sound coil of loudspeaker comprises a cylinder surrounded with four layers of coils. With the fixed number of layers and the fixed structure of conducting wire, following disadvantages become apparent for the conventional sound coils:    1. To produce a certain level of output power, the loudspeaker has to be provided with a certain length of coils; and thus production costs cannot be reduced.    2. To cope with the fixed length of coils, it is unlikely to reduce the circumference of cylinder and, therefore, the size of loudspeaker cannot be reduced.
The inventor has studied the foregoing problems thoroughly and conducted numerous tests to improve the structure of sound coils; then created the present invention.